Method, system, and device for delivery of process gas

ABSTRACT

A method and chemical delivery system and device are provided. One method includes contacting a non-aqueous hydrazine solution with a carrier gas and/or vacuum and delivering a gas stream comprising hydrazine to a critical process or application. One chemical delivery system and device includes a non-aqueous hydrazine solution having a vapor phase that is in contact with a carrier gas and/or vacuum. One device includes a chamber for containing a liquid comprising at least one volatile process chemical, such as a non-aqueous hydrazine solution, a hydrogen peroxide solution, or another suitable process chemical, and a head space from which the volatile can be drawn using a carrier gas and/or vacuum. Another method useful in the present invention involves drawing a process chemical from a device as a disclosed herein using a carrier or vacuum and delivering the process chemical to a critical process or application.

TECHNICAL FIELD

Methods, systems, and devices for the vapor phase delivery of highpurity process gases in micro-electronics and other critical processapplications.

BACKGROUND

Various process gases may be used in the manufacturing and processing ofmicro-electronics. In addition, a variety of chemicals may be used inother environments demanding high purity gases, e.g., criticalprocesses, including without limitation microelectronics applications,wafer cleaning, wafer bonding, photolithography mask cleaning, atomiclayer deposition, chemical vapor deposition, flat panel displays,disinfection of surfaces contaminated with bacteria, viruses and otherbiological agents, industrial parts cleaning, pharmaceuticalmanufacturing, production of nano-materials, power generation andcontrol devices, fuel cells, power transmission devices, and otherapplications in which process control and purity are criticalconsiderations. In those processes, it is necessary to deliver specificamounts of certain process gases under controlled operating conditions,e.g., temperature, pressure, and flow rate.

For a variety of reasons, gas phase delivery of process chemicals ispreferred to liquid phase delivery. For applications requiring low massflow for process chemicals, liquid delivery of process chemicals is notaccurate or clean enough. Gaseous delivery would be desired from astandpoint of ease of delivery, accuracy and purity. One approach is tovaporize the process chemical component directly at or near the point ofuse. Vaporizing liquids provides a process that leaves heavycontaminants behind, thus purifying the process chemical. Gas flowdevices are better attuned to precise control than liquid deliverydevices. Additionally, micro-electronics applications and other criticalprocesses typically have extensive gas handling systems that makegaseous delivery considerably easier than liquid delivery. However, forsafety, handling, stability, and/or purity reasons, many process gasesare not amenable to direct vaporization.

There are numerous process gases used in micro-electronics applicationsand other critical processes. Ozone is a gas that is typically used toclean the surface of semiconductors (e.g., photoresist stripping) and asan oxidizing agent (e.g., forming oxide or hydroxide layers). Oneadvantage of using ozone gas in micro-electronics applications and othercritical processes, as opposed to prior liquid-based approaches, is thatgases are able to access high aspect ratio features on a surface. Forexample, according to the International Technology Roadmap forSemiconductors (ITRS), current semiconductor processes should becompatible with a half-pitch as small as 20-22 nm. The next technologynode for semiconductors is expected to have a half-pitch of 10 nm, andthe ITRS calls for <7 nm half-pitch in the near future. At thesedimensions, liquid-based chemical processing is not feasible, becausethe surface tension of the process liquid prevents it from accessing thebottom of deep holes or channels and the corners of high aspect ratiofeatures. Therefore, ozone gas has been used in some instances toovercome certain limitations of liquid-based processes, because gases donot suffer from the same surface tension limitations. Plasma-basedprocesses have also been employed to overcome certain limitations ofliquid-based processes. However, ozone- and plasma-based processespresent their own set of limitations, including, inter alia, cost ofoperation, insufficient process controls, undesired side reactions, andinefficient cleaning.

Other problems relate to the temperature necessary for successfuldeposition. With respect to silicon nitride (SiN) for example, ammonia(NH₃) is currently often used at temperatures in excess of 500° C. oreven 600° C. It is expensive to maintain such high temperatures fordeposition and it would be preferable to deposit at lower temperatures.In addition, new semiconductor device technologies have stringentthermal budgets, which inhibit the use of elevated temperatures over400° C. Hydrazine (N₂H₄) presents an opportunity to explore lowertemperatures in part because of the favorable thermodynamics ofhydrazine resulting in lower deposition temperatures and a spontaneousreaction to form nitrides. Although reported in the literature (Burtonet al. J. Electrochem. Soc., 155(7) D508-D516 (2008)), hydrazine usagehas not been adopted commercially due to the serious safety concernswith using hydrazine. Substituted hydrazines suffer from the drawback ofleading to unwanted carbon contamination. Thus, there is a need todevelop a safer method for using hydrazine for either depositionprocesses or for delivery to other critical process applications.

The gas phase use of hydrazine has been limited by safety, handling, andpurity concerns. Hydrazine has been used for rocket fuel and can be veryexplosive. Semiconductor industry protocol for safe handling of thismaterial is very limited. Therefore, a technique is needed to overcomethese limitations and, specifically, to provide substantially water-freegaseous hydrazine suitable for use in micro-electronics and othercritical process applications.

Similarly, as explained in PCT Publication No. 2014014511 by Rasirc,Inc., which is hereby incorporated by reference herein, the gas phaseuse of hydrogen peroxide in critical process applications has been oflimited utility, because highly concentrated hydrogen peroxide solutionspresent serious safety and handling concerns and obtaining highconcentrations of hydrogen peroxide in the gas phase has not beenpossible using existing technology.

SUMMARY OF CERTAIN EMBODIMENTS

Methods, systems, and devices for delivering a substantially water-freeprocess gas stream, particularly a hydrazine-containing gas stream, areprovided. The methods, systems, and devices are particularly useful inmicro-electronics applications and other critical processes. Generally,the methods comprise (a) providing a non-aqueous hydrazine solutionhaving a vapor phase comprising an amount of hydrazine vapor; (b)contacting a carrier gas or vacuum with the vapor phase; and (c)delivering a gas stream comprising substantially water-free hydrazine toa critical process or application. In many embodiments, the amount ofhydrazine in the vapor phase is sufficient to provide hydrazine directlyto a critical process or application without further concentrating orprocessing the hydrazine-containing gas stream. In many embodiments, thenon-aqueous hydrazine solution includes a stabilizer. In certainembodiments, the methods further include removing one or morestabilizers from the gas stream. By adjusting the operating conditionsof the methods, e.g., the temperature and pressure of the carrier gas orvacuum, the concentration of the hydrazine solution, and the temperatureand pressure of the hydrazine solution, hydrazine can be precisely andsafely delivered as a process gas. In certain embodiments, the amount ofhydrazine in the vapor phase and delivered to the critical process orapplication can be controlled by adding energy to the hydrazinesolution, e.g., thermal energy, rotational energy, or ultrasonic energy.In many embodiments of the invention, the non-aqueous hydrazine is neathydrazine or hydrazine that is substantially free of water.

Systems and devices for delivering hydrazine using the methods describedherein are also provided. Generally, the systems and devices comprise(a) a non-aqueous hydrazine solution having a vapor phase comprising anamount of hydrazine vapor; (b) a carrier gas or vacuum in fluid contactwith the vapor phase; and (c) an apparatus for delivering a gas streamcomprising hydrazine to a critical process or application. In manyembodiments, the non-aqueous hydrazine solution includes one or morestabilizers. In certain embodiments, the systems and devices furtherinclude an apparatus for removing one or more stabilizers from the gasstream. In many embodiments, the amount of hydrazine in the vapor phaseis sufficient to provide hydrazine directly to a critical process orapplication without further concentrating or processing thehydrazine-containing gas stream. In certain embodiments, the apparatusfor delivering a gas stream comprising hydrazine is an outlet of a headspace, containing the vapor phase, that is connected directly orindirectly to a micro-electronics application or other critical processsystem, allowing the hydrazine containing gas stream to flow from thehead space to the application or process in which it will be used. Thehydrazine delivery assembly (HDA) described herein is one such device.By adjusting the operating conditions of the systems and devices, e.g.,the temperature and pressure of the carrier gas or vacuum, theconcentration of the hydrazine solution, and the temperature andpressure of the hydrazine solution, hydrazine can be precisely andsafely delivered as a process gas. In certain embodiments, the amount ofhydrazine in the vapor phase and delivered to the critical process orapplication can be controlled by adding energy to the hydrazinesolution, e.g., thermal energy, rotational energy, or ultrasonic energy.

Many of the embodiments of the methods, systems, and devices disclosedherein utilize a membrane in contact with the hydrazine-containingsolution. The use of the membrane has safety advantages. In certainembodiments, the membrane wholly or partially separates thehydrazine-containing solution from the hydrazine-containing vapor phase.By eliminating access between the vapor phase and the liquid phase, asudden decomposition in the vapor phase of the hydrazine would belimited and not cause a corresponding decomposition in the liquid phasedue to the presence of the membrane.

Also disclosed herein are devices for containing a liquid comprising avolatile chemical or chemical composition (e.g., hydrazine, hydrogenperoxide, water, alcohols, amines, or ammonium hydroxide), wherein thedevice comprises a head space where vapor comprising the chemical orcomposition is accessible as a process gas to be incorporated into aprocess gas stream. The process gas stream comprising the chemical orcomposition is typically delivered to a critical process application. Incertain embodiments, the device comprises (a) a chamber containing aliquid comprising a volatile chemical or chemical composition, (b) ahead space comprising a vapor phase that includes the volatile chemicalor chemical composition in the gas phase, (c) a inlet port through whicha carrier gas stream can enter the chamber, and (d) a protected outletport through which a process gas stream comprising carrier gas and thevolatile chemical or chemical composition can exit the head space. Incertain embodiments, the head space is a portion of the chamber. Incertain alternative embodiments, the head space is distinct from thechamber and in fluid communication with the chamber to allow thevolatile chemical or chemical composition in the gas phase to move fromthe chamber into head space. In many embodiments, a membrane facilitatesthe transfer of the volatile chemical or chemical composition from theliquid into the gas phase. The configuration of the membrane may varyaccording to the particular application and process design. In someembodiments, the membrane wholly or partially separates the liquid fromthe head space. In certain embodiments, the membrane comprises a tubeconnected to the inlet port such that all or a portion of the carriergas travels through the membrane. In such embodiments, the membrane tubemay also travel through a portion of the liquid in the chamber andterminate in the head space. The protected outlet port comprises anapparatus to ensure that the volatile chemical or chemical compositionentering the exit port is substantially in the gas phase, i.e.,substantially free of liquid phase material, such as droplets, mists, orfogs.

The methods, systems, and devices described herein are generallyapplicable to a wide variety of process gas streams, particularlynon-aqueous hydrazine solutions wherein the hydrazine solutions containnon-aqueous components.

In certain embodiments, the solution comprises substantially purehydrazine, meaning hydrazine in which no other chemicals aredeliberately included but allowing for incidental amounts of impurities.In certain embodiments, the solution comprises from about 5% to about99% by weight of hydrazine, or from about 90% to about 99%, from about95% to about 99%, from about 96% to about 99%, from about 97% to about99%, from about 98% to about 99%, or from about 99% to about 100% byweight of hydrazine, with the remaining components comprising solventsand/or stabilizers. In some embodiments, the solution compriseshydrazine at concentrations greater than 99.9% purity and, in someembodiments, the solution comprises hydrazine at concentrations ofgreater than 99.99%. Selection of an appropriate non-aqueous hydrazinesolution will be determined by the requirements of a particularapplication or process.

In certain embodiments, the non-aqueous hydrazine solution comprises, inaddition to hydrazine, one or more suitable solvents. For example, thenon-aqueous hydrazine solution may comprise a PEGylated solvent, whereinthe PEGylated solvent is a liquid when at a temperature of about 25° C.The term “PEGylated solvent” refers to a solvent containing a covalentlyattached poly(ethylene glycol) moiety. One exemplary PEGylated solventis poly(ethylene glycol) dimethyl ether. In some embodiments, thesuitable solvent is selected from low molecular weight polymers oroligomers of polyaniline, polypyrrole, polypyridine orpolyvinylalchohol. A low molecular weight polymer is one such that whencombined with hydrazine, the combined solution has a viscosity of about35 centipoises (cp) or less. Other examples of solvents include glymessuch as monoglyme, diglyme, triglyme, higlyme, and tetraglyme. Furtherexamples include a range of PEGylated dimethyl ethers such as PolyglycolDME 200, Polyglycol DME 250, Polyglycol DME 500, Polyglycol DME 1000, orPolyglycol DME 2000. Still other solvents include hexamethylphosoramideand hexamethylenetetramine. In some embodiments, the non-aqueoushydrazine solution comprises from about 30% to about 69% by weight andranges in between including between about 65% to about 69% by weight ofhydrazine. The remainder of the solution may comprise, for example, oneor more PEGylated solvents such as poly(ethylene glycol) dimethyl ether.For instance, the hydrazine solution may comprise from about 32% to 35%by weight of PEGylated solvent such as poly(ethylene glycol) dimethylether or other suitable solvents. In other embodiments, less than about65% hydrazine is used and more than about 35% of a PEGylated solventsuch as poly(ethylene glycol) dimethyl ether is used such as PolyglycolDME 250.

The methods, systems, and devices provided herein can employ a varietyof membranes. The membrane is typically a selectively permeablemembrane, particularly a substantially gas-impermeable membrane, e.g., aperfluorinated ion exchange membrane, such as a NAFION® membrane. Incertain embodiments, the NAFION® membrane may be chemically treatede.g., with an acid, base, or salt to modify its reactivity. For example,in certain embodiments, the NAFION® membrane may be treated in a way toform the ammonium species. By using certain selectively permeablemembranes, which typically are substantially gas-impermeable membranesand specifically NAFION® membranes and its derivatives, theconcentration of the hydrazine gas in the resultant gas stream may bealtered relative to the hydrazine concentration that would be obtaineddirectly from the vapor of the hydrazine solution in the absence of amembrane. In certain embodiments, the hydrazine gas concentration isamplified (i.e., higher than) the concentration that would be expectedfrom the vapor of the hydrazine solution absent the membrane.Preferably, the concentration of hydrazine is amplified using themethods, systems, and devices disclosed herein.

In another embodiment, the membrane is a copolymer of tetrafluroethyleneand sulfonyl fluoride vinyl ether. One such example of such a membranecan be made from Aquivon® which is sourced from Solvay. A specificAquivon® polymer is known as P98S and is provided as pellets.

The methods, systems, and devices provided herein may further compriseremoving one or more components from the hydrazine containing gas streamto produce a purified hydrazine containing gas stream, e.g., using adevice that selectively or non-selectively removes components from thegas stream. Preferred devices would be devices that substantially removea non-reactive process gas from the hydrazine containing gas stream,while the amount of hydrazine in the gas stream is relativelyunaffected. For example, a device may remove any non-aqueous solvents orstabilizers from the gas stream, including without limitation any tracesof water or non-aqueous solvents. For example, the devices may furthercomprise a purifier positioned downstream of the head space.Particularly preferred purifier devices are membrane contactors,molecular sieves, activated charcoaland other adsorbents, if they havethe desired characteristics to meet the application or processrequirements. A preferred characteristic of the gas removal device isthe ability to remove certain component(s) in a relatively selectivemanner while allowing the remaining component(s) to remain in thehydrazine gas stream relatively unaffected.

The systems and devices provided herein may further comprise variouscomponents for containing and controlling the flow of the gases andliquids used therein. For example, the systems and devices may furthercomprise mass flow controllers, valves, check valves, pressure gauges,regulators, rotameters, and pumps. The systems and devices providedherein may further comprise various heaters, thermocouples, andtemperature controllers to control the temperature of various componentsof the devices and steps of the methods.

Additional objects and advantages of the invention will be set forth inpart in the description which follows, and in part will be obvious fromthe description, or maybe learned by practice of the invention. Theobjects and advantages of the invention will be realized and attained bymeans of the elements and combinations particularly pointed out in theembodiments and claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention.

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate several embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a diagram illustrating a part of a membrane assembly usefulin certain embodiments of the present invention.

FIG. 1B is a diagram illustrating an embodiment of a hydrazine deliveryassembly (HDA) according to certain embodiments of the presentinvention.

FIG. 2A is a cross-sectional view of an embodiment of an HDA accordingto certain embodiments of the present invention.

FIG. 2B is a cross-sectional view of an embodiment of an HDA accordingto certain embodiments of the present invention.

FIG. 3 is a P&ID of a manifold that can be used to test methods,systems, and devices for hydrazine delivery according to certainembodiments of the present invention.

FIG. 4 is a P&ID of a manifold that can be used to test methods,systems, and devices for hydrazine delivery according to certainembodiments of the present invention.

FIG. 5 is a P&ID of a manifold that can be used to test methods,systems, and devices for hydrazine delivery according to certainembodiments of the present invention.

FIG. 6 is a diagram illustrating a membrane assembly and HDA accordingto certain embodiments of the present invention.

FIG. 7 is a P&ID of a manifold that can be used to test methods,systems, and devices for hydrazine delivery according to certainembodiments of the present invention.

FIG. 8 is a chart depicting hydrazine gas concentration and temperatureover time according to an embodiment of the present invention, usingsubstantially pure hydrazine as a liquid source.

FIG. 9 is a P&ID of a manifold that can be used to test methods,systems, and devices for hydrazine delivery according to certainembodiments of the present invention.

FIG. 10 is a chart depicting hydrazine gas concentration and temperatureover time according to an embodiment of the present invention, usinganhydrous 98% hydrazine as a liquid source.

FIG. 11 is a chart depicting hydrazine gas concentration and temperatureover time according to an embodiment of the present invention, using 65%hydrazine in poly(ethylene glycol) dimethyl ether as a liquid source.

FIG. 12 is a diagram illustrating an HDA according to certainembodiments of the present invention.

FIG. 13 is a P&ID of a manifold that can be used to test methods,systems, and devices for hydrazine delivery according to certainembodiments of the present invention.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

The term “process gas” as used herein is a broad term, and is to begiven its ordinary and customary meaning to a person of ordinary skillin the art (and is not to be limited to a special or customizedmeaning), and refers without limitation to a gas that is used in anapplication or process, e.g., a step in the manufacturing or processingof micro-electronics and in other critical processes. Exemplary processgases are reducing agents, oxidizing agents, inorganic acids, organicacids, inorganic bases, organic bases, and inorganic and organicsolvents. A preferred process gas is hydrazine.

The term “reactive process gas” as used herein is a broad term, and isto be given its ordinary and customary meaning to a person of ordinaryskill in the art (and is not to be limited to a special or customizedmeaning), and refers without limitation to a process gas that chemicallyreacts in the particular application or process in which the gas isemployed, e.g., by reacting with a surface, a liquid process chemical,or another process gas.

The term “non-reactive process gas” as used herein is a broad term, andis to be given its ordinary and customary meaning to a person ofordinary skill in the art (and is not to be limited to a special orcustomized meaning), and refers without limitation to a process gas thatdoes not chemically react in the particular application or process inwhich the gas is employed, but the properties of the “non-reactiveprocess gas” provide it with utility in the particular application orprocess.

The term “carrier gas” as used herein is a broad term, and is to begiven its ordinary and customary meaning to a person of ordinary skillin the art (and is not to be limited to a special or customizedmeaning), and refers without limitation to a gas that is used to carryanother gas through a process train, which is typically a train ofpiping. Exemplary carrier gases are nitrogen, argon, hydrogen, oxygen,CO2, clean dry air, helium, or other gases that are stable at roomtemperature and atmospheric pressure.

The term “head space” as used herein is a broad term, and is to be givenits ordinary and customary meaning to a person of ordinary skill in theart (and is not to be limited to a special or customized meaning), andrefers without limitation to a volume of gas in fluid contact with ahydrazine solution that provides at least a portion of the gas containedin the head space. There may be a permeable or selectively permeablebarrier wholly or partially separating the head space that is optionallyin direct contact with the hydrazine solution. In those embodimentswhere the membrane is not in direct contact with the hydrazine solution,more than one head space may exist, i.e. a first head space directlyabove the solution that contains the vapor phase of the solution and asecond head space separated from the first head space by a membrane thatonly contains the components of the first space that can permeate themembrane, e.g., hydrazine. In those embodiments with a hydrazinesolution and a head space separated by a substantially gas-impermeablemembrane, the head space may be located above, below, or on any side ofthe hydrazine solution, or the head space may surround or be surroundedby the hydrazine solution. For example, the head space may be the spaceinside a substantially gas-impermeable tube running through thehydrazine solution or the hydrazine solution may be located inside asubstantially gas-impermeable tube with the head space surrounding theoutside of the tube.

The term “substantially gas-impermeable membrane” as used herein is abroad term, and is to be given its ordinary and customary meaning to aperson of ordinary skill in the art (and is not to be limited to aspecial or customized meaning), and refers without limitation to amembrane that is relatively permeable to other components that may bepresent in a gaseous or liquid phase, e.g., hydrazine, but relativelyimpermeable to other gases such as, but not limited to, hydrogen,nitrogen, oxygen, carbon monoxide, carbon dioxide, hydrogen sulfide,hydrocarbons (e.g., ethylene), volatile acids and bases, refractorycompounds, and volatile organic compounds.

The term “ion exchange membrane” as used herein is a broad term, and isto be given its ordinary and customary meaning to a person of ordinaryskill in the art (and is not to be limited to a special or customizedmeaning), and refers without limitation to a membrane comprisingchemical groups capable of combining with ions or exchanging with ionsbetween the membrane and an external substance. Such chemical groupsinclude, but are not limited to, sulfonic acid, carboxylic acid,sulfonamide, sulfonyl imide, phosphoric acid, phosphinic acid, arsenicgroups, selenic groups, phenol groups, and salts thereof.

The term “permeation rate” as used herein is a broad term, and is to begiven its ordinary and customary meaning to a person of ordinary skillin the art (and is not to be limited to a special or customizedmeaning), and refers without limitation to the rate at which a specificchemical, e.g., hydrazine, or a chemical composition a permeates amembrane. The permeation rate may be expressed as an amount of thechemical or composition of interest that permeates a particular surfacearea of membrane during a period of time, e.g., liters per minute persquare inch (L/min/in²).

The term “non-aqueous solution” as used herein is a broad term, and isto be given its ordinary and customary meaning to a person of ordinaryskill in the art (and is not to be limited to a special or customizedmeaning), and refers to a solution comprising hydrazine and optionallyother components and containing less than 10% by weight of water.Exemplary non-aqueous solutions include those containing less than 2%,0.5%, 0.1%, 0.01%, 0.001% or less water.

The term “stabilizer” as used herein is a broad term, and is to be givenits ordinary and customary meaning to a person of ordinary skill in theart (and is not to be limited to a special or customized meaning), andrefers to a chemical that prevents the decomposition or reaction ofprocess chemical, such as hydrazine or hydrogen peroxide. In certainembodiments, the stabilizer is non-volatile and is not present in thevapor phase in more than an insubstantial amount. In certainembodiments, the stabilizer can be removed from the process gas streamby exposing the process gas stream to an adsorbent or passing theprocess gas stream through a cold trap. In certain embodiments thatinclude a membrane separating the non-aqueous hydrazine solution fromthe vapor phase, the stabilizer may not permeate the membrane.

The methods, systems, and devices disclosed herein provide advantageousdelivery of volatile process components to a critical processapplication. In many embodiments, the methods, systems, and devicesdisclosed herein are particularly applicable to hydrazine. Certaindevices disclosed herein are also applicable to other volatile processcomponents.

In certain embodiments, the advantageous hydrazine delivery provided bythe present invention, and specifically the methods, systems, anddevices of certain embodiments described herein, may be obtained using amembrane contactor. In a preferred embodiment, a non-porous membrane isemployed to provide a barrier between the hydrazine solution and thehead space that is in fluid contact with a carrier gas or vacuum.Preferably, hydrazine rapidly permeates across the membrane, while gasesare excluded from permeating across the membrane into the solution. Insome embodiments the membrane may be chemically treated with an acid,base, or salt to modify the properties of the membrane.

In certain embodiments, the hydrazine is introduced into a carrier gasor vacuum through a substantially gas-impermeable ionic exchangemembrane. Gas impermeability can be determined by the “leak rate.” Theterm “leak rate” as used herein is a broad term, and is to be given itsordinary and customary meaning to a person of ordinary skill in the art(and is not to be limited to a specialized or customized meaning), andrefers without limitation to the volume of a particular gas thatpenetrates the membrane surface area per unit of time. For example, asubstantially gas-impermeable membrane could have a low leak rate ofgases (e.g., a carrier gas) other than a process gas (e.g., hydrazine),such as a leak rate of less than about 0.001 cm3/cm2/s under standardatmospheric temperature and pressure. Alternatively, a substantiallygas-impermeable membrane can be identified by a ratio of thepermeability of a process gas vapor compared to the permeability ofother gases. Preferably, the substantially gas-impermeable membrane ismore permeable to such process gases than to other gases by a ratio ofat least 10,000:1, such as a ratio of at least about 20,000:1, 30,000:1,40,000:1, 50,000:1, 60,000:1, 70,000:1, 80,000:1, 90,000:1 or a ratio ofat least 100,000:1, 200,000:1, 300,000:1, 400,000:1, 500,000:1,600,000:1, 700,000:1, 800,000:1, 900,000:1 or even a ratio of at leastabout 1,000,000:1. However, in other embodiments, other ratios that areless than 10,000:1 can be acceptable, for example 1.5:1, 2:1, 3:1, 4:1,5:1, 6:1, 7:1, 8:1, 9:1, 10:1; 50:1, 100:1, 500:1, 1,000:1, or 5,000:1or more.

In certain embodiments, the membrane is an ion exchange membrane, suchas a polymer resin containing exchangeable ions. Preferably, the ionexchange membrane is a fluorine-containing polymer, e.g.,polyvinylidenefluoride, polytetrafluoroethylene (PTFE), ethylenetetrafluoride-propylene hexafluoride copolymers (FEP), ethylenetetrafluoride-perfluoroalkoxyethylene copolymers (PFE),polychlorotrifluoroethylene (PCTFE), ethylene tetrafluorideethylenecopolymers (ETFE), polyvinylidene fluoride, polyvinyl fluoride,vinylidene fluoride-trifluorinated ethylene chloride copolymers,vinylidene fluoride-propylene hexafluoride copolymers, vinylidenefluoridepropylene hexafluoride-ethylene tetrafluoride terpolymers,ethylene tetrafluoridepropylene rubber, and fluorinated thermoplasticelastomers. Alternatively, the resin comprises a composite or a mixtureof polymers, or a mixture of polymers and other components, to provide acontiguous membrane material. In certain embodiments, the membranematerial can comprise two or more layers. The different layers can havethe same or different properties, e.g., chemical composition, porosity,permeability, thickness, and the like. In certain embodiments, it canalso be desirable to employ a layer (e.g., a membrane) that providessupport to the filtration membrane, or possesses some other desirableproperty.

The ion exchange membrane is preferably a perfluorinated ionomercomprising a copolymer of ethylene and a vinyl monomer containing anacid group or salts thereof. Exemplary perfluorinated ionomers include,but are not limited to, perfluorosulfonic acid/tetrafluoroethylenecopolymers (“PFSA-TFE copolymer”) and perfluorocarboxylicacid/tetrafluoroethylene copolymer (“PFCA-TFE copolymer”). Thesemembranes are commercially available under the tradenames NAFION® (E.I.du Pont de Nemours & Company), 3M Ionomer (Minnesota Mining andManufacturing Co.), FLEMION® (Asashi Glass Company, Ltd.), and ACIPLEX®(Asashi Chemical Industry Company), and Aquivon® (Solvay).

In preparing a hydrazine containing gas stream, a hydrazine solution canbe passed through the membrane. The term “passing a hydrazine solutionthrough a membrane” as used herein is a broad term, and is to be givenits ordinary and customary meaning to a person of ordinary skill in theart (and is not to be limited to a special or customized meaning), andrefers without limitation to contacting a first side of a membrane withthe hydrazine solution, such that the hydrazine passes through themembrane, and obtaining a hydrazine containing gas stream on theopposite side of the membrane. The first and second sides can have theform of substantially flat, opposing planar areas, where the membrane isa sheet. Membranes can also be provided in tubular or cylindrical formwhere one surface forms the inner position of the tube and an opposingsurface lies on the outer surface. The membrane can take any form, solong as the first surface and an opposing second surface sandwich a bulkof the membrane material. Depending on the processing conditions, natureof the hydrazine solution, volume of the hydrazine solution's vapor tobe generated, and other factors, the properties of the membrane can beadjusted. Properties include, but are not limited to physical form(e.g., thickness, surface area, shape, length and width for sheet form,diameter if in fiber form), configuration (flat sheet(s), spiral orrolled sheet(s), folded or crimped sheet(s), fiber array(s)),fabrication method (e.g., extrusion, casting from solution), presence orabsence of a support layer, presence or absence of an active layer(e.g., a porous prefilter to adsorb particles of a particular size, areactive prefilter to remove impurities via chemical reaction orbonding), and the like. It is generally preferred that the membrane befrom about 0.5 microns in thickness or less to 2000 microns in thicknessor more, preferably from about 1, 5, 10, 25, 50, 100, 200, 300, 400, or500 microns to about 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400,1500, 1600, 1700, 1800, or 1900 microns. When thinner membranes areemployed, it can be desirable to provide mechanical support to themembrane (e.g., by employing a supporting membrane, a screen or mesh, orother supporting structure), whereas thicker membranes may be suitablefor use without a support. The surface area can be selected based on themass of vapor to be produced.

Certain embodiments of the methods, systems, and devices providedherein, in which a carrier gas or vacuum can be used to deliversubstantially water-free hydrazine, are shown by reference to theFigures.

According to certain embodiments of the present invention, a hydrazinedelivery assembly (HDA) is provided. An HDA is a device for deliveringhydrazine into a process gas stream, e.g., a carrier gas used in acritical process application, e.g., microelectronics manufacturing orother critical process applications. An HDA may also operate undervacuum conditions. An HDA may have a variety of different configurationscomprising at least one membrane and at least one vessel containing anon-aqueous hydrazine solution and a head space separated from thesolution by membrane.

FIGS. 1A and 1B depict different views of one embodiment of an HDA 100and a membrane assembly 110 that forms part of an HDA that can be usedas provided herein. FIG. 1A shows membrane assembly 110 comprising aplurality of membranes 120, for example, 5R NAFION® membrane, which canbe configured as lumens. As depicted in FIG. 1A, membranes 120configured into lumens are inserted into a collector plate 130 through aplurality of holes within collector plate 130. Membrane assembly 110also comprises a plurality of polytetrafluoroethylenene (PTFE) rods 140inserted into collector plate 130. As shown in FIG. 1B, as part of HDA100, membrane assembly 110 comprises membrane lumens 120 spanningcollector plates 130. HDA 100 further comprises endcaps 150 at each endof membrane assembly 110. Endcaps 150 further include branches 160,which can be fitted with tubing to provide access to the interior of HDA100, e.g., to fill, empty, clean, or refill the HDA.

FIG. 2A and FIG. 2B show a cross-sectional view of two embodiments ofHDAs according to certain embodiments of the present invention.

HDA 200A, as shown in FIG. 2A, comprises a membrane assembly 210A withina shell housing 220A and end caps 230A configured to couple to shellhousing 220A. Membrane assembly 210A comprises of a plurality ofmembranes 240A, which can be configured as lumens. The number of lumenscan vary depending on various factors, including the size of the lumens,the size of HDA 200A, and the operating conditions of the HDA. Incertain embodiments, an HDA may contain up to 1000 membrane lumens, upto 500 lumens, up to 200 lumens, up to 100 lumens, or up to 50 lumens.For example, HDA 200A may have about 20-50 membrane lumens. The membranelumens can be constructed from a perfluorinated sulfonic acid membrane,for example, 5R NAFION® membrane. The end caps 230A and shell housing220A can be formed from a variety of materials, for example, PTFE,stainless steel (such as 316 stainless steel), or other suitablematerials. Each end cap 230A further comprises a gas connection 231A.Gas connection 231A can take the form of a variety of connectionconfigurations and sizes, for example, ¼″ VCR, ¼″ NPT, or other suitableconnectors.

HDA 200B, as shown in FIG. 2B, comprises a membrane assembly 2108 withina shell housing 220B and end caps 230B configured to couple to shellhousing 220B. Membrane assembly 210B can be comprised of a plurality ofmembrane lumens (not shown). The number of lumens can vary depending onvarious factors, including the size of the lumens, the size of HDA 200B,and the operating conditions of the HDA. In certain embodiments, an HDAmay contain up to 1000 membrane lumens, up to 500 lumens, up to 200lumens, up to 100 lumens, or up to 50 lumens. For example, HDA 200B mayhave about 20-50 membrane lumens. The membrane lumens can be constructedfrom a perfluorinated sulfonic acid membrane, for example, 5R NAFION®membrane. The end caps 230B and shell housing 220B can be formed from avariety of materials, for example, PTFE, stainless steel (such as 316stainless steel), or other suitable materials. Each end cap 230B cancomprise a gas connection 231B. Gas connection 2318 can take the form ofa variety of connection configurations and sizes, for example, ¼″ VCR,¼″ NPT, or other suitable connectors.

According to the various embodiments, the HDA can be filled with anon-aqueous hydrazine containing solution, while maintaining a headseparated from the hydrazine containing solution by a membrane. Becausethe membrane is permeable to hydrazine and substantially impermeable tothe other components of the solution, the head space will containsubstantially pure hydrazine vapor in a carrier gas or vacuum, dependingupon the operating conditions of the process.

According to various embodiments, an HDA can be constructed similarly tothe devices described in commonly assigned U.S. Pat. No. 7,618,027,which is herein incorporated by reference.

According to certain embodiments, a device for containing liquid and avapor phase comprising a volatile chemical or composition, which may bea non-aqueous hydrazine containing solution, is provided, wherein themembrane contacts the volatile chemical or composition on one side ofthe membrane and a carrier gas stream on the other side of the membrane.FIG. 12 depicts one example of such a device 1200, comprising (a) achamber containing a liquid comprising a volatile chemical or chemicalcomposition, (b) a head space comprising a vapor phase that includes thevolatile chemical or chemical composition in the gas phase, (c) a inletport through which a carrier gas stream can enter the chamber, and (d) aprotected outlet port through which a process gas stream comprisingcarrier gas and the volatile chemical or chemical composition can exitthe head space.

As shown in FIG. 12, carrier gas 1214 enters through the inlet port1202. Carrier gas 1214 then moves through the membrane 1208 which isattached to inlet port 1202 by seal 1216. In certain embodiments, seal1216 provides a leak tight connection between inlet port 1202 and 1208.In certain embodiments, seal 1216 may not be leak tight or may be apartial seal to allow a portion of carrier gas 1214 to flow into headspace 1210. In certain embodiments, membrane 1208 is a tubular membrane,but the geometry of the may be adapted according to the requirements ofthe particular application or process in which the device is used. Oneside of membrane 1208 is configured to contact liquid 1212, whichcomprises a volatile chemical or composition capable of diffusing acrossmembrane 1208. Carrier gas 1214 flows through membrane 1208 on a sideopposite the side that is in contact with liquid 1212. Process gasstream 1218, comprising the volatile chemical or composition in the gasphase, is formed as the volatile chemical or composition diffuses acrossthe membrane into the carrier gas stream. Membrane 1208 allows certaincomponents of liquid 1212 to diffuse across the membrane into thecarrier gas stream to provide a select process gas stream 1218, whilepreventing other components of liquid 1212 from diffusing into theprocess gas stream 1218 (e.g., water, metal ions, other ioniccontaminants, and other contaminants). At the outlet 1222 of membrane1208, process gas stream 1218, comprising carrier gas 1214 and a processchemical from liquid 1212, enters headspace 1210. Thus, the pressureinside of tubular membrane 1208 matches the pressure in head space 1210and, thus, the vapor pressure of liquid 1212, which prevents thecollapse of the membrane when the outlet pressure is lower than theinlet pressure. Process gas 1220 contained in headspace 1210 exits thedevice through the splash guard 1206 and outlet port 1204 for deliveryto a critical process 1224. In this embodiment, splash guard 1206retains the open end 1222 of the tubular membrane 1208 such that theprocess gas stream exiting passing through outlet port 1204 issubstantially free of liquid contaminants, e.g., droplets, particles,mists, or fogs.

In many embodiments, e.g., the embodiment shown in FIG. 12, the membraneis partially immersed in the liquid source. Submerging the membraneincreases the mass transfer surface area and the residence time thecarrier gas has to fully saturate with gas generated from the liquidsource. The membrane may be long enough to reach the bottom of thecanister and then back up to the surface above the liquid. The membranecan range from about 3.0 inches in length or less to about 72 inches inlength or more, including lengths in between such as about 5, 10, 15,20, 25, 30, or 35 inches to about 40, 45, 50, 55, 60, or 65 inches ormore. The immersed part of the membrane can be coiled to increase liquidto membrane surface area. Multiple membranes can be used and run inparallel to further increase liquid to membrane surface area. Themembrane may be about 0.002 inches thick or less to about 0.010 inchesthick or more, including about 0.003, 0.004, or 0.005 inches thick toabout 0.006, 0.007, 0.008, or 0.009 inches thick or more. The diameterof the membrane may be about 0.062 inches or less to about 0.250 inchesor more, including 0.070, 0.080, 0.090, 0.100, 0.110, 0.120, 0.130,0.140, or 0.150 inches to about 0.160, 0.170, 0.180, 0.190, 0.200,0.210, 0.220, 0.230, or 0.240 inches or more.

In many embodiments, e.g., the embodiment shown in FIG. 12, the deviceincludes a splash guard. The splash guard limits the volume, velocity,or nature of the liquid exiting through the outlet of the device. Thesplash guard is capable of maintaining the outlet of the tubularmembrane above the liquid. In several embodiments, the splash guard hasa long narrow slit in the conductive path to the outlet barb whichprevents droplets from entering the gas stream leaving the outlet port.The splash guard is made of a material compatible with the chemistriesbeing used in the liquid source and carrier gas. For example,low-reactive materials such as, but not limited to, stainless steel,aluminum, or plastic may be used. The splash guard may be attached tothe container by fitting onto the outlet barb. In some embodiments, thesplash guard is about 1.50 inches in height, the slit is about 0.03inches in width and about 1.25 inches in height, and the slit's lengthis the same as the diameter of the splash guard which is about 1.00inch.

Although a primary purpose of the present disclosure is gas phasedelivery of non-aqueous hydrazine according the methods, systems, anddevices provided herein, other process chemicals capable of diffusingacross the membrane may be used in the liquid source and, therefore, mayalso be part of process gas stream 1218 exiting the outlet port, includehydrogen peroxide, water, alcohols (such as ethanol, methanol, ethyleneglycol, pentanol, glycerol, xylitol, or isopropyl alcohol), amines (suchas hydrazine, methylamine, ethanolamine, dimethylamine, aniline,trimethylamine, triphenylamine, aziridine, or methylethanolamine), orammonium hydroxide. These process chemicals, whether in the liquidsource or in the process gas, may be used alone or in combination. Incertain embodiments, the liquid source may include a polar solvent,whereas in certain other embodiments the liquid source may include anonpolar solvent.

The devices disclosed herein that are capable of containing a liquidsource comprising at least one process chemical and delivering at leastone process chemical in the gas phase to a critical process application,e.g., the device shown in FIG. 12, may be used in conjunction with themethods, systems, and other devices of the present invention, or theymay be used as standalone devices for delivering a process gas stream toa critical process application.

An embodiment according to an aspect of the methods, systems, anddevices provided herein is described below by reference to a manifold300, as shown by reference to FIG. 3. According to the embodiment shownby reference to FIG. 3, a carrier gas 310 flows through the head spaceof HDA 320, which can be an HDA as described above. A mass flowcontroller (MFC) 330, for example, Unit UFC-1260A 1 slm, can be used tocontrol the flow rate of carrier gas 310, which can be set to 1 slm, forexample. Analysis of the amount of hydrazine in the gas stream mayrequire dilution of the resultant gas stream, which can be accomplishedwith dilution gas 350. A mass flow controller (MFC) 340, for example, aUnit UFC-1260A 10 slm can be used to control the flow rate of dilutiongas 350. Carrier gas 310 and dilution gas 350 can be supplied by a gassource 360, which can be typically nitrogen or other suitable carriergas. A valve 370 can be used to isolate the dilution line when it is notrequired. Check valves 371, 372 can be placed downstream of both MFC 330and MFC 340 to protect them from possible hydrazine exposure. A 60 psigpressure gauge 373 can be placed between MFC 330 and check valve 372 toinsure that the manifold's pressure does not exceed the maximum pressureallowed by hydrazine analyzer 380, e.g., 5 psig.

The nitrogen pressure can be maintained with a forward pressureregulator 374, typically set to 15 psig. A thermocouple 375 can measurethe temperature of nitrogen carrier gas 310 before it enters HDA 320 forhydrazine addition. A thermocouple 376 can measure the temperature ofthe hydrazine solution in HDA 100. A thermocouple 377 can measure thegas temperature before entering hydrazine analyzer 380. Hydrazineanalyzer 380 can pull in a sample of carrier gas 310 to measure thehydrazine concentration. Manifold 300 can further comprise a relativehumidity/resistance temperature detector (RH/RTD) probe 378. A heatertape 390 can be placed on certain sections as indicated in FIG. 3. Themanifold's temperature can be controlled in two separate zones, themembrane assemblies and the remaining tubing, with a Trilite Equipment &Technologies Controller and a Watlow 96 Controller, respectively. Theentire manifold can be set up inside of a fume hood.

The embodiment shown by reference to FIG. 3 is set up as a testapparatus to measure the amount of hydrazine introduced into a carriergas stream under various operating conditions of an HDA. It will beunderstood that a similar apparatus can be used to deliver hydrazine toa critical process application.

FIG. 4 is a P&ID of a test manifold 400, according to anotherembodiment, used to demonstrate delivery of hydrazine under vacuumconditions, according to the methods, systems, and devices providedherein. According to the embodiment shown by reference to FIG. 4, avacuum pump 410 removes gas from the hydrazine containing vapor side(i.e., head space) of HDA 420, which can be an HDA as described above.For example, vacuum pump 410 can be maintained at about 24 mmHg using avalve 480 and a pressure gauge 430. A gas source 440 can be maintainedat a pressure of about 2 psig with a forward pressure regulator 450. Avalve 460 can be used as a flow restrictor. A thermocouple 470 can beplaced inside the filling tube of a HDA 420 to measure the solution'stemperature inside the shell of HDA 420. The test involves contactingthe vapor side, i.e., head space, of HDA 420 to a vacuum produced byvacuum pump 410 while holding HDA 420 at a constant temperature. A heattape 490 can be placed around HDA 420 to allow for constant temperaturecontrol of the hydrazine containing solution within HDA 420. Thisvacuum-based method, system, and device is particularly preferred innumerous micro-electronics and other critical process applications thatare operated at relatively reduced pressures (i.e., under vacuum).

The embodiment shown by reference to FIG. 4 is set up as a testapparatus to measure the amount of hydrazine introduced into a carriergas stream under various operating conditions of an HDA. It will beunderstood that a similar apparatus can be used to deliver hydrazine toa critical process application.

FIG. 5 is a P&ID of a test manifold 500, according to anotherembodiment, used to demonstrate delivery of hydrazine, according to anaspect of the methods, systems, and devices provided herein. As shown inFIG. 5, a nitrogen carrier gas 510 can flow through the head space ofHDA 520, which can be an HDA as described above. A mass flow controller(MFC) 530, for example, a Brooks SLA5850S1EAB1B2A1 5 slm, can be used tocontrol the flow rate of nitrogen carrier gas 510, which can be set to 1slm, for example. Analysis of the amount of hydrazine in the gas streammay require dilution of the resultant gas stream, which can beaccomplished with dilution gas 550. A mass flow controller (MFC) 540,for example, a Brooks SLA5850S1EAB1B2A1 10 slm, can be used to controlthe flow rate of a nitrogen dilution gas 550. Nitrogen carrier gas 510and nitrogen dilution gas 550 can be supplied by a nitrogen gas source560. A valve 570 can be used to isolate the dilution line when desired.A pair of check valves 571, 572 can be placed downstream of both MFC 530and MFC 540 to protect them from possible hydrazine exposure. A pressuregauge 573, for example, 100 psi gauge, can be placed between MFC 530 andHDA 520 to insure that the manifold's pressure does not exceed anymaximum pressure allowed by an analyzer 580.

The nitrogen pressure can be maintained with a forward pressureregulator 574, for example set to 25 psig. A thermocouple 575 canmeasure the temperature of nitrogen carrier gas 510 before it enters HDA520 for hydrazine addition. Within HDA 520, nitrogen carrier gas 510 canflow through the membrane tubes and hydrazine vapor can permeate throughthe membrane from the solution contained within the shell housing andcombined with carrier gas 510. A thermocouple 576 can measure thetemperature of the hydrazine solution in HDA 520. A thermocouple 577 canmeasure the gas temperature exiting HDA 520. In this embodiment, ananalyzer 580 can be used to measure the hydrazine concentration in thegas stream. Analyzer 580 can be, for example, a MiniRAE 3000, which hasa photoionization detector with an 11.7 eV gas discharge lamp. Analyzer580 can, for example, pull a sample of the hydrazine containing gasstream to measure the hydrazine concentration. A thermocouple 578 can beused to measure the gas temperature before entering analyzer 580. Athermocouple 581 can be used to measure the temperature of nitrogendilution gas 550.

Manifold 500 can further comprise a catalytic converter 585 configuredto remove the hydrazine by converting it into nitrogen and hydrogen.Downstream of catalytic converter 585 can be a probe 579, for example, aE+E Elektronik EE371 humidity transmitter configured to measure the dewpoint (DP) and moisture concentration. Downstream of probe 579 can be avent. A heater tape 590 can be placed on certain sections as indicatedin FIG. 5. The manifold's temperature can be controlled in four separatezones, indicated by the dotted line boxes, with Watlow EZZone® 96controllers, respectively. The entire manifold can be set up inside of afume hood.

The embodiment shown by reference to FIG. 5 is set up as a testapparatus to measure the amount of hydrazine introduced into a carriergas stream under various operating conditions of an HDA. It will beunderstood that a similar apparatus can be used to deliver hydrazine toa critical process application.

FIG. 6 is a diagram illustrating a cross-section of a membrane assemblyuseful in certain embodiments of the present invention when a singlemembrane is used. The membrane assembly may be incorporated into, forexample, an HDA such as one shown in FIG. 1B. As shown in FIG. 6, in oneembodiment of the invention, the membrane may be a single membrane lumensleeved over a stainless steel tube containing a calibrated number ofholes to provide a specific membrane surface area available forpermeation. The sleeved stainless steel tube is encased inside an outertube to form the Hydrazine Delivery Assembly (HDA). Liquid hydrazine isfilled inside the space between the inner and outer tubes. A carrier gasis directed to flow through the inner tube to carry hydrazine vaporwhich has permeated the membrane to the desired process.

FIG. 7 is a P&ID of a manifold that can be used to test methods,systems, and devices for hydrazine delivery according to certainembodiments of the present invention. According to this embodiment, acarrier gas (CG) flows through the head space of the HDA, labeled“Vaporizer,” which can be an HDA as described above. A mass flowcontroller (MFC 1), for example, a 5 slm Brook's SLA5850S1EAB1B2A1 massflow controller, can be used to control the flow rate of carrier gasinto the HDA. Analysis of the amount of hydrazine in the gas streamexiting the vaporizer may involve first diluting the resultant gasstream, which can be accomplished with a dilution gas (DG-1). A massflow controller (MFC 2), for example, a 10 slm Brook's SLA5850S1EAB1B2A1mass flow controller, can be used to control the flow rate of dilutiongas DG-1. A separate line of dilution gas DG-2 may be supplied to aportion of the manifold positioned within a Glove Bag.

Carrier gas CG and dilution gases DG-1 and DG-2 can be supplied by a GasSource, which can be typically nitrogen or other suitable carrier gas.In some embodiments such as the one shown in FIG. 7, the carrier gas anddilution gases share the same gas source. In other embodiments, thecarrier gas and dilution gases may have independent gas sources. ValvesV-1 and V-2 can be used to control gas flow into the HDA/DG-1 dilutionline or into the DG-2 dilution line/Glove Bag, respectively. Checkvalves CV-1 and CV-2 can be placed downstream of MFC 2 and MFC 1,respectively, to protect them from possible hydrazine exposure. Apressure gauge PG-2 can be placed between CV-2 and the Vaporizer tomeasure pressure upstream of the Vaporizer.

The carrier gas pressure can be maintained with a forward pressureregulator PR1 and measured with pressure gauge PG-1. A forward pressureregulator PR2 can be used to control the flow of dilution gas DG-2through the Gas Bag. A thermocouple T-1 can measure the temperature ofthe hydrazine solution in the Vaporizer. A thermocouple T-2 can measurethe gas temperature after a mixing loop and before entering a hydrazineanalyzer. The MiniRAE 3000 is one example of a hydrazine analyzer.Heater tape HT can be placed on certain sections, such as on theVaporizer, a portion of the dilution gas DG-1 line, and lines downstreamof the Vaporizer as indicated in FIG. 7. The manifold may also comprisecatalytic converters downstream of the Vaporizer and Glove Bag todecompose hydrazine to nitrogen and hydrogen. The entire manifold can beset up inside of a fume hood.

The embodiment shown by reference to FIG. 7 is set up as a testapparatus to measure the amount of hydrazine introduced into a carriergas stream under various operating conditions of an HDA. It will beunderstood that a similar apparatus can be used to deliver hydrazine toa critical process application.

Example 1 Experimental

In the examples of the disclosure, membranes were prepared by purchasingsulfonyl fluoride perfluorinated polymers, extruding them, and thenhydrolyzing them by methods known in the art to form membranes. Suchmembranes are also referred to as NAFION® herein.

The manifold illustrated in FIG. 7 was utilized for a test procedure inthis Example. The test procedure involved obtaining stable gas phasehydrazine readings utilizing a non-aqueous, substantially pure hydrazinesolvent as a liquid source.

A NAFION® vaporizer (P/N#200801-01) was used for this experiment. Thisvaporizer included a single 5R NAFION® membrane sleeved over a ⅛″ SS(stainless steel) tubing. The SS tubing had twenty 0.06″ diameter holes,allowing for a total permeable area of 0.06 in². The tubing was enclosedby a ⅜″ SS tubing with two ¼″ fill ports for the shell side. The volumeof the shell side was approximately 8 ml.

The manifold was setup in a fume hood. The nitrogen pressure wasmaintained at 25 psig with a forward pressure regulator (PR-1) andmeasured with a pressure gauge (PG-1). Two valves (V-1 and V-2) wereused to terminate gas flow through vaporizer and/or dilution line. A 5slm Brook's SLA5850S1EAB1B2A1 Mass Flow Controller (MFC-1) was used tocontrol the carrier gas flow rate. A 10 slm Brook's SLA5850S1EAB1B2A1Mass Flow Controller (MFC-2) was used to control the dilution gas flowrate. Check valves (CV-1 and CV-2) were placed downstream of both MFCsto protect them from being exposed to hydrazine. A forward pressureregulator with gauge (PR-2) was used to control flow of nitrogen throughgas bag. The pressure upstream of the vaporizer was measured with apressure gauge (PG-2). A J-type thermocouple (TC-1) was attached to thevaporizer as a control point for the heater tape. The carrier gas wasmixed with the nitrogen from the dilution line downstream of thevaporizer. A J-type thermocouple (TC-2) was used to monitor gastemperature after mixing. A MiniRAE 3000, which has a photoionizationdetector (PID) with an 11.7 eV gas discharge lamp, was used to measurethe hydrazine concentration in the gas stream. The test manifold andglove bag vent lines had catalytic converters that decomposed thehydrazine to nitrogen and hydrogen. The vaporizer, a portion of thedilution line, and the test manifold downstream of the vaporizer washeat-traced with heater tape.

For this experiment, the carrier gas flow was set to 1 slm. The dilutiongas flow was initially set to 1 slm and would be increased if theconcentration was above 2000 ppm (upper detection limit of the MiniRae3000). The manifold was heated to keep the gas temperature at 30° C. atTC-2.

FIG. 8 represents the results from this experiment with the carrier gasflow and dilution gas flow at 1 slm. As shown, the hydrazine output wasdirectly affected by the gas temperature once the system was stabilized.This effect was demonstrated when the temperature setpoint for thisexperiment was raised from 30° C. to 31° C. 78 minutes into the test.The average concentration of hydrazine was 2426 ppm for the last 26minutes of the test. The result is a permeation rate of 0.04043L/min/in² under these conditions.

Example 2

The manifold illustrated in FIG. 9 was utilized for test procedures inthis Example. The test procedures involved obtaining stable gas phasehydrazine readings using either an anhydrous 98% hydrazine solvent as aliquid source, or a solution of 65% hydrazine in poly(ethylene glycol)dimethyl ether solvent (Mn=250) as a liquid source.

A NAFION® vaporizer (P/N#200846-A) was used for these experiments. Thisvaporizer consisted of a single 5R NAFION® membrane sleeved over a ⅛″ SStubing. The SS tubing had ten 0.06″ diameter holes, allowing for a totalpermeable area of 0.03 in². The tubing is enclosed by a ⅜″ SS tubingwith two ¼″ fill ports for the shell side. The volume of the shell sidewas approximately 8 ml.

The manifold was setup in a fume hood. An Entegris 500KF Gatekeeperpurifier was used to remove oxygen, water, and hydrocarbons from the gasstream. Two valves (V-1 and V-2) were used to terminate gas flow throughglove box and the test manifold respectively. The nitrogen flow insidethe glove box was maintained with a forward pressure regulator and thepressure measured with a pressure gauge (PG-1). A check valve (CV-1) wasplaced upstream of the glove box to prevent back streaming of thehydrazine. A forward pressure regulator with gauge was used to maintaina gas pressure of 25 psig upstream of the MFCs. A 5 slm Brook'sSLA5850S1EAB1B2A1 Mass Flow Controller (MFC-1) was used to control thecarrier gas flow rate. A 10 slm Unit Mass Flow Controller (MFC-2) wasuse to control the dilution gas flow rate. Check valves (CV-2 and CV-3)were placed downstream of both MFCs to protect them from being exposedto hydrazine.

A single-lumen vaporizer was used to add hydrazine vapor to the gasstream. The mixing loop was used to mix nitrogen from the dilution lineand hydrazine vapor in the carrier gas downstream of the vaporizer. AJ-type thermocouple (TC-1) was used to monitor gas temperature aftermixing. A MiniRAE 3000, which has a photoionization detector (PID) withan 11.7 eV gas discharge lamp, was used to measure the hydrazineconcentration in the gas stream. The test manifold and glove box ventlines had scrubbers that catalytically decompose the hydrazine tonitrogen and hydrogen. A valve (V-3) was used to create backpressure inthe glove box and for isolation.

For this Example, two solutions were tested at room temperature. Onesolution was anhydrous 98% hydrazine (Sigma Aldrich). The secondsolution was 65% w/w hydrazine (ρ=1.029 g/ml) in poly(ethylene glycol)dimethyl ether (ρ=1.03 g/ml). An 8 ml solution was made with 5.2 ml ofanhydrous 98% hydrazine and 2.8 ml of poly(ethylene glycol) dimethylether.

Before each test run, the MiniRAE 3000 was calibrated with 100 ppmisobutene gas standard. Once the analyzer was attached the testmanifold, the solution was added to the vaporizer without gas flowingthrough the test manifold. Once filled, the carrier gas flow was set to1 slm and the dilution gas flow was to 1 slm. The dilution gas flowwould be increased if the concentration was above 2000 ppm (upperdetection limit of the MiniRAE 3000). Readings of the gas temperatureand hydrazine concentration were recorded. Stabilization would bedetermined as when the vaporizer output change was less than 5 ppm/min.

FIG. 10 represents the results from the anhydrous 98% hydrazine with thecarrier gas flow and dilution gas flow at 1 slm for 330 minutes. Afterstabilization was reached in ten minutes, the average concentration was1482.7 ppm±102.2 ppm at an average temperature of 23.6° C.±0.4° C. Thus,the concentration was stable to within less than 10% of the averageconcentration. The result is an average permeation rate of 0.04942L/min/in² under these conditions. This hydrazine permeation rate wasclose to the 0.04043 L/min/in² permeation rate measured during theprevious test done in Example 1.

FIG. 11 represents the results from the 65% hydrazine in poly(ethyleneglycol) dimethyl ether with the carrier gas flow and dilution gas flowat 1 slm for 320 minutes. After stabilization was reached in 30 minutes,the average concentration was 1190.6 ppm±27.6 ppm with an averagetemperature of 24.5° C.±0.3° C. The result was an average permeationrate of 0.03969 L/min/in² under these conditions. Spikes in hydrazineconcentration shown near time zero in FIGS. 10 and 11 reflect artifactsin the measuring instruments and are not deemed to be accurate orrelevant.

The permeation was 19.7% less with the 65% hydrazine/poly(ethyleneglycol) dimethyl ether solution in comparison to the 98% hydrazinesolution. An encouraging attribute shown with the 65% hydrazine/solventwas that the output was more stable over time than the 98% hydrazinehydrate solution. In 290 minutes the 98% hydrazine solutionconcentration output decreased 263 ppm. However, the 65%hydrazine/poly(ethylene glycol) dimethyl ether solution concentrationoutput only decreased 23 ppm in 290 minutes. The overall result with thepoly(ethylene glycol) dimethyl ether presents it as a viable solvent forsafe hydrazine vapor delivery.

By controlling the temperature of the hydrazine containing solution and,as applicable, the carrier gas or vacuum, particular hydrazineconcentrations can be delivered The stability of the hydrazineconcentration in the process gas stream can be controlled to less thanabout 20%, e.g., less than about 18%, less than about 16%, less thanabout 14%, or less than about 12%, or less than about 10%. In apreferred embodiment, the stability of the hydrazine concentration inthe process gas stream can be controlled to less than about 10% of theaverage concentration within one standard deviation, e.g., less thanabout 9%, less than about 8%, less than about 7%, less than about 6%,less than about 5%, less than about 4%, less than about 3%, less thanabout 2%, or even less than about 1%. The average concentration does notinclude measurements by the instrument prior to achieving equilibrium.For example, the measurement in FIG. 11 of hydrazine concentrationincludes what appears to be a spike of up to about 1900 ppm. This spikeis an instrument factor and not an actual measurement as it takes on theorder of about 10 minutes or more for the instrument to stabilize andall average concentration readings hereunder take such stabilizationinto account. The selection of a particular hydrazine concentration willdepend on the requirements of the application or process in which thehydrazine containing process gas will be used. In certain embodiments,the hydrazine containing gas stream may be diluted by adding additionalcarrier gas. In certain embodiments, the hydrazine containing gas streammay be combined with other process gas streams prior to or at the timeof delivering hydrazine to an application or process. Alternatively oradditionally, any residual solvent or stabilizers, or contaminantspresent in the hydrazine containing process gas may be removed in apurification (e.g., dehumidification) step using a purifier apparatus.

Example 3

The manifold illustrated in FIG. 13 was utilized for test procedures inthis Example. The Brute™ vaporizer 1306 was assembled with a PTFE splashguard on the outlet barb and a new lumen assembly. Brute™ vaporizer 1306was filled with 200 mL of a liquid source solution comprising hydrogenperoxide and the lid was assembled. The test system 1300 was assembledas shown in FIG. 13. Manometer 1310 was connected to the displayreadout. All valves 1302, 1304, 1308, and 1312 were closed and vacuumpumps 1318, 1320, and 1322 were off. Cold trap bath 1316 was filled withliquid nitrogen. Outlet back pressure valve (BPV) 1304 was closed andvalve 1312 was opened. Vacuum pumps 1318, 1320, and 1322 were turned on,the cold trap bath 1316 was opened, and the equilibrium pressure wasrecorded. Outlet BPV 1304 was quickly opened to shock vaporizer 1306with low pressure. Observation perfluoroalkoxy (PFA) Tube 1324 wasmonitored for signs of droplets of the liquid source solution. Vaporizer1306 was exposed to vacuum until the pressure was constant. Valve 1312was turned off and the rate of rise was recorded in minute intervals.The test was repeated several times. The splash guard prevented liquidsolution from entering the outlet of vaporizer 1306 at pressures below 1torr.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

1-126. (canceled)
 127. A method comprising: (a) providing a non-aqueoussolution comprising a process chemical in a device configured to containa liquid and a vapor phase, wherein the non-aqueous solution has a vaporphase comprising an amount of anhydrous vapor of the process chemical;(b) contacting a carrier gas or vacuum with the vapor phase to form agas stream; and (c) delivering the gas stream comprising the anhydrousvapor to a critical process or application, wherein the process chemicalis hydrazine or hydrogen peroxide.
 128. The method of claim 127, furthercomprising changing the concentration of at least one component of thevapor phase by changing at least one of the following parameters: (a)the temperature of the non-aqueous solution, (b) the pressure of thenon-aqueous solution, (c) the concentration of the non-aqueous solution,(d) the temperature of the carrier gas, (e) the pressure of the carriergas or vacuum, and (f) the flow rate of the carrier gas.
 129. The methodof claim 127, wherein at least one membrane is disposed in the device,the membrane being configured to at least partially separate the vaporphase from the non-aqueous solution.
 130. The method of claim 129,wherein the anhydrous vapor permeates the membrane at a faster rate thanany other component of the non-aqueous solution.
 131. The method ofclaim 129, wherein the membrane is an ion exchange membrane.
 132. Themethod of claim 127, further comprising removing contaminants from thegas stream.
 133. The method of claim 127, wherein the carrier gas isselected from the group consisting of nitrogen, argon, hydrogen, cleandry air, helium, and other gases that are stable at room temperature andatmospheric pressure.
 134. The method of claim 127, further comprisingchanging the concentration of at least one component of the vapor phaseby adding energy to the non-aqueous solution.
 135. The method of claim127, wherein the non-aqueous solution further comprises a solventselected from the group consisting of polymers or oligomers ofpolyaniline, polypyrrole, polypyridine, and polyvinylalchohol, whereinthe viscosity of the solution is about 35 cp or less.
 136. The method ofclaim 127, wherein the non-aqueous solution further comprises a solventselected from monoglyme, diglyme, triglyme, higlyme, tetraglyme,Polyglycol DME 200, Polyglycol DME 250, Polyglycol DME 500, PolyglycolDME 1000, Polyglycol DME 2000, hexamethylphosoramide orhexamethylenetetramine.
 137. The method of claim 127, wherein thenon-aqueous solution further comprises a PEGylated solvent, wherein thePEGylated solvent is a liquid when at a temperature of about 25° C. 138.The method of claim 127, wherein the non-aqueous solution furthercomprises poly(ethylene glycol) dimethyl ether.
 139. The method of claim127, wherein the non-aqueous solution is a non-aqueous hydrazinesolution comprising from about 25% to about 69% by weight of hydrazine.140. The method of claim 139, wherein the non-aqueous hydrazine solutioncomprises from about 65% to about 69% by weight of hydrazine.
 141. Themethod of claim 127, wherein the non-aqueous solution contains less than0.1%, 0.01%, or 0.001% water.
 142. The method of claim 127, wherein theconcentration of anhydrous vapor delivered in the gas stream is stableto within about 5% of the average concentration delivered or to withinabout 3% of the average concentration delivered.
 143. A chemicaldelivery system comprising: (a) a device configured to contain a liquidand a vapor phase; (b) a non-aqueous solution comprising a processchemical provided in the device, wherein the non-aqueous solution has avapor phase comprising an amount of anhydrous vapor of the processchemical; (c) a carrier gas or vacuum in fluid contact with the vaporphase and configured to form a gas stream containing the anhydrousvapor, wherein the process chemical is hydrazine or hydrogen peroxideand wherein the device has an outlet configured to deliver the gasstream to a critical process or application.
 144. The chemical deliverysystem of claim 143, further comprising one or more componentsconfigured to change the concentration of at least one component of thevapor phase by changing at least one of the following parameters: (a)the temperature of the non-aqueous solution, (b) the pressure of thenon-aqueous solution, (c) the concentration of the non-aqueous solution,(d) the temperature of the carrier gas, (e) the pressure of the carriergas or vacuum, and (f) the flow rate of the carrier gas.
 145. Thechemical delivery system of claim 143, wherein the device includes atleast one membrane configured to at least partially separate the vaporphase from the non-aqueous solution.
 146. The chemical delivery systemof claim 145, wherein the membrane is an ion exchange membrane.
 147. Thechemical delivery system of claim 143, wherein the carrier gas isselected from the group consisting of nitrogen, argon, hydrogen, cleandry air, helium, and other gases that are stable at room temperature andatmospheric pressure.
 148. The chemical delivery system of claim 143,wherein the device further comprises a component configured to addenergy to the non-aqueous hydrazine solution.
 149. The chemical deliverysystem of claim 143, wherein the non-aqueous solution further comprisesa solvent.
 150. The chemical delivery system of claim 149, wherein thesolvent is poly(ethylene glycol) dimethyl ether.
 151. The chemicaldelivery system of claim 143, wherein the non-aqueous solution is anon-aqueous hydrazine solution comprising from about 25% to about 69% byweight of hydrazine.
 152. A device comprising: (a) a housing comprisingan inlet port and an outlet port, the housing being configured tocontain a liquid and a vapor phase; (b) a tubular membrane having afirst end and a second end, the tubular membrane being disposed withinthe housing and configured to be in contact with the liquid when presentin the house, wherein the first end is in fluid communication with theinlet port; (c) a splash guard disposed within the housing and in fluidcommunication with the outlet port, wherein the splash guard isconfigured to retain the second end of the tubular membrane and toprevent liquid from exiting the housing.
 153. The device of claim 152,wherein the tubular membrane is an ion exchange membrane.